A quantitative immunocytochemical study of Na+,K+-ATPase in rat hepatocytes after STZ-induced diabetes and dietary fish oil supplementation

Because diabetes causes alterations in hepatic membrane fatty acid content, these changes may affect the Na+,K+-ATPase. In this study we documented th e effects of streptozotocin (STZ)-induced diabetes on hepatic Na+,K+-ATPase catalytic alpha(1)-subunit and evaluated whether these changes could be no rmalized by fish oil supplementation. Two groups of diabetic rats received fish oil or olive oil supplementation. Both groups had a respective control group. We studied the localization of catalytic alpha(1)-subunit on bile c analicular and basolateral membranes using immunocytochemical methods and c onfocal laser scanning microscopy, and the Na+,K+-ATPase activity, membrane fluidity, and fatty acid composition on isolated hepatic membranes. A decr ease in the alpha(1)-subunit was observed with diabetes in the bile canalic ular membranes, without changes in basolateral membranes. This decrease was partially prevented by dietary fish oil. Diabetes induces significant chan ges as documented by enzymatic Na+,K+-ATPase activity, membrane fluidity, a nd fatty acid content, whereas little change in these parameters was observ ed after a fish oil diet. In conclusion, STZ-induced diabetes appears to mo dify bile canalicular membrane integrity and dietary fish oil partly preven ts the diabetes-induced alterations.